/*
 * Copyright (C) 2012-2017 DataStax Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.datastax.driver.core;

import com.datastax.driver.core.exceptions.AuthenticationException;

import java.net.InetSocketAddress;

/**
 * Provides {@link Authenticator} instances for use when connecting
 * to Cassandra nodes.
 * <p/>
 * See {@link PlainTextAuthProvider} for an implementation which uses SASL
 * PLAIN mechanism to authenticate using username/password strings
 */

/**
 * 认证提供者
 */
public interface AuthProvider {

    /**
     * A provider that provides no authentication capability.
     * <p/>
     * This is only useful as a placeholder when no authentication is to be used.
     */
    public static final AuthProvider NONE = new AuthProvider() {
        @Override
        public Authenticator newAuthenticator(InetSocketAddress host, String authenticator) {
            throw new AuthenticationException(host,
                    String.format("Host %s requires authentication, but no authenticator found in Cluster configuration", host));
        }
    };

    /**
     * The {@code Authenticator} to use when connecting to {@code host}
     *
     * @param host          the Cassandra host to connect to.
     * @param authenticator the configured authenticator on the host.
     * @return The authentication implementation to use.
     */
    public Authenticator newAuthenticator(InetSocketAddress host, String authenticator) throws AuthenticationException;
}
